Molecular interactions in wood fibre suspensions

Recent research in our laboratory on chemical changes and interactions in mechanical pulping and bleaching as well as in the wet end of papermaking is reviewed, Dissolved and colloidal components released from wood into process waters in mechanical pulping and bleaching strongly affect the production of wood-containing papers, especially in mills with low fresh water use. Alkaline peroxide bleaching gives dramatic effects not only to the dissolved and colloidal substances but also to the fibres. The alkaline conditions of peroxide bleaching results e g in a threefold amount of acidic groups in fibres. Pectins, composed mainly of galacturonic acids, and glucomannans play especially significant roles in mechanical pulp suspensions.